1. Field of the Invention
The present invention relates to a ratchet wrench, especially a ratchet wrench which is adjustably applicable to various screws fastening elements as well as continuously and easily turned in operation.
2. Description of the Related Art
The ratchet wrench is a common hand tool. As shown in FIG. 1, a conventional ratchet wrench 90 comprises a handle 91 and a head 92 on which there is a hollow working portion 93 with tooth tips 921 on its edge. With a screw fastening element (e.g., a sleeve or a nut not shown in the figure) placed in the hollow working portion 93 during operation, the handle 91 is turned to drive the head 92 for the screw fastening element screwed. Notwithstanding the foregoing, the conventional ratchet wrench 90 is not taken as an economic design because of a fixed size of its hollow working portion 93, which must fit one screw fastening element with a corresponding size, or preparation of alternative ratchet wrenches 90 with multiple hollow working portions 93 for all types of screw fastening elements to be screwed. Therefore; a ratchet wrench 90 applicable to any screw fastening element's distinct size has been designed, for example, Adjustable Wrench (U.S. Pat. No. 4,838,132) is provided with a moveable jaw member, which is moved within the head's hollow working portion to contact a screw fastening element to be screwed, and depends on its adjustable forward or backward status to change the hollow working portion's inner space and fit a distinct screw fastening element.
Notwithstanding the previously mentioned patent which is effective in regulating a moveable jaw member's moving direction, forward or backward, and applicable to multiple screw fastening elements and features economic efficiency to simplify the quantity of tools, the patent still has some drawbacks, for instance, the adjustable wrench based on the moveable jaw member for screw operation of multiple screw fastening elements is not an ideal design obviously because it is complicated and wasteful of time during operation and is not stable with a larger screw fastening element held by the moveable jaw member in a comparatively smaller range of screw operation. Additionally, it is rather inconvenient to operate the patent adjustable wrench, for example, the shifted moveable jaw member must be readjusted with the adjustable wrench failing to be turned 360 degrees in a limited working space and withdrawn again to acquire a working space prepared for next screwing. That is, the patent adjustable wrench is not provided with a mechanism designed to be constantly operated and deserves to be corrected. Thus, how to eliminate drawbacks of a ratchet wrench based on the prior art in use should be one issue to be solved or overcome by the industry or talents.
Considering drawbacks and an unideal design of a ratchet wrench based on the prior art, the inventor exerted himself to study solutions and develop a fast-operated, convenient and adjustable ratchet wrench favorable to the general public and progress of the industry and created this invention after long-term thinking.